SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd494823e4397850afc933cbeed0bfe3e6f6e52cbba0fb28f25e94fcb599aa34b' 
  AND token = '9MR+VshXyV/ZHBGZDetdgZzH2Nu0ufQCFKQGSjSHPoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}